Walker Point
A planned sonde swap at Walker Point was not able to be completed due to weather concerns. Overall, water quality at Walker Point was fair to good this week. Weather conditions were dry this week, no precipitation recorded at T.F. Green. Blackstone River flow was highest at the beginning of the week, above the 22-year daily median flow, and decreased as the week continued, generally staying below the 22-year daily median flow. Salinity at Walker Point surface averaged 16.4 ppt and ranged from 6.5 ppt to 26.9 ppt. At the bottom, salinity averaged 28.8 ppt and ranged from 20.9 ppt to 30.6 ppt. Temperatures this week averaged 13.8 °C at the surface and 16.2 °C at the bottom. Surface temperatures ranged from 11.4 °C to 15.2 °C, while bottom temperatures ranged from 14.2 °C to 16.9 °C.
Dissolved oxygen (DO) at Walker Point remained above the hypoxia threshold (2.9 mg/L) at the surface and bottom for the entire week. Surface DO averaged 8.7 mg/L and ranged from 7.2 to 10.6 mg/L. Bottom water DO concentration averaged 5.4 mg/L and ranged from 3.5 mg/L to 7.1 mg/L. Chlorophyll ranged from low to mildly elevated levels throughout the week, averaging 1.8 ug/L at the surface and 2.6 ug/L at the bottom, with little evidence of any phytoplankton blooms occurring throughout the week. Maximum chlorophyll readings reached 15.0 ug/L in bottom waters on the afternoon of October 24th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
Overall, water quality was good at Bullock Reach this week. Salinity averaged 27.7 ppt, 29.8 ppt, and 31.8 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged from 21.4 to 30.2 ppt, mid salinity ranged from 26.9 to 31.3 ppt, and bottom salinity ranged from 29.7 to 32.9 ppt. Surface temperature averaged 14.9 °C and ranged from 12.9 °C to 16.0 °C. Mid temperatures averaged 15.3 °C and ranged from 14.3 °C to 16.4 °C. Bottom temperatures averaged 15.6 °C and ranged from 14.5 °C to 16.8 °C.
DO at Bullock Reach did not experience hypoxic conditions (i.e., DO < 2.9 mg/L) during the week. Surface DO averaged 7.9 mg/L and ranged from 7.2 to 9.3 mg/L. In the mid waters, DO averaged 7.6 mg/L and ranged from 6.7 to 8.3 mg/L. At the bottom, DO averaged 6.9 mg/L and ranged from 5.6 to 8.0 mg/L. Chlorophyll readings remained low to moderately elevated this week, with evidence of moderate phytoplankton blooms occurring during the week. Readings averaged 1.4 µg/L at the surface, 4.0 µg/L at mid-depth, and 2.5 µg/L at the bottom. The maximum chlorophyll was observed in mid waters at 61.5 µg/L on the afternoon of October 21st.